Cache parse trees

This prevents EvalState::resetFileCache() from parsing everything all
over again.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 146f21255034..d0f298e168e9 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -90,6 +90,14 @@ public:
 private:
     SrcToStore srcToStore;
 
+    /* A cache from path names to parse trees. */
+#if HAVE_BOEHMGC
+    typedef std::map<Path, Expr *, std::less<Path>, traceable_allocator<std::pair<const Path, Expr *> > > FileParseCache;
+#else
+    typedef std::map<Path, Expr *> FileParseCache;
+#endif
+    FileParseCache fileParseCache;
+
     /* A cache from path names to values. */
 #if HAVE_BOEHMGC
     typedef std::map<Path, Value, std::less<Path>, traceable_allocator<std::pair<const Path, Value> > > FileEvalCache;